JP6382429B2 - Base station, user terminal, processor, and method - Google Patents

Description

  The present invention relates to a base station, a user terminal, and a processor in a mobile communication system that supports D2D communication.

  In 3GPP (3rd Generation Partnership Project), which is a standardization project for mobile communication systems, introduction of inter-terminal (Device to Device: D2D) communication is being studied as a new function after Release 12 (see Non-Patent Document 1).

  In D2D communication, a plurality of adjacent user terminals perform direct communication without going through a core network. That is, the data path of D2D communication does not go through the core network. On the other hand, the data path of normal communication (cellular communication) of the mobile communication system passes through the core network.

3GPP Technical Report “TR 22.803 V1.1.0” November 2012

  In the current specification, there is no mechanism for appropriately controlling D2D communication. For this reason, there exists a problem that D2D communication is not utilized effectively.

  Therefore, the present invention provides a base station, a user terminal, and a processor in a mobile communication system that can effectively utilize D2D communication.

  According to one embodiment, a base station in a mobile communication system that has a user terminal capable of establishing a connection with a cell managed by the base station and supports D2D communication that is direct inter-terminal communication is the D2D communication. A transmitter that transmits a measurement request to the user terminal for requesting measurement of the reception intensity of a signal transmitted from another user terminal performing the reception, and the reception intensity measured based on the measurement request A reception unit that receives measurement information from the user terminal; and a control unit that determines whether the user terminal is capable of the D2D communication based on the measurement information. The control unit performs control to instruct to perform the D2D communication when the user terminal determines that the D2D communication is possible.

  According to the base station, the user terminal, and the processor according to the present invention, D2D communication can be effectively utilized.

FIG. 1 is a configuration diagram of an LTE system. FIG. 2 is a block diagram of the UE. FIG. 3 is a block diagram of the eNB. FIG. 4 is a protocol stack diagram of a radio interface in the LTE system. FIG. 5 is a configuration diagram of a radio frame used in the LTE system. FIG. 6 is a diagram illustrating a data path in cellular communication. FIG. 7 is a diagram illustrating a data path in D2D communication. FIG. 8 is a sequence diagram illustrating an operation example of the mobile communication system according to the embodiment.

[Outline of Embodiment]
The base station according to the embodiment is a base station in a mobile communication system that has a user terminal capable of establishing a connection with a cell managed by the base station and supports D2D communication that is direct inter-terminal communication. The base station, based on the measurement request, a transmission unit that transmits a measurement request to the user terminal that requests measurement of reception strength of a signal transmitted from another user terminal that performs the D2D communication. A receiving unit configured to receive measurement information indicating the measured reception intensity from the user terminal; and a control unit configured to determine whether the user terminal is capable of the D2D communication based on the measurement information. The control unit performs control to instruct to perform the D2D communication when the user terminal determines that the D2D communication is possible.

  In the base station according to the embodiment, the transmission unit transmits the measurement request when the user terminal is performing cellular communication with the other user terminal via a core network.

  In the base station according to the embodiment, when the other user terminal is located in the cell that establishes a connection with the user terminal or an adjacent cell adjacent to the cell, the user terminal It is determined that D2D communication is possible, and control for transmitting the measurement request is performed.

  In the base station according to the embodiment, when the control unit determines that the user terminal exists near the other user terminal based on the position information of the user terminal and the position information of the other user terminal. And control to transmit the measurement request.

  In the base station according to the embodiment, the control unit performs control to transmit the measurement request when the proximity notification indicating that the user terminal exists near the other user terminal is received.

  In the base station according to the embodiment, when the control unit receives discovery information indicating that a discovery signal for discovering the counterpart terminal for D2D communication has been received from the user terminal or the other user terminal In addition, control for transmitting the measurement request is performed.

  In the base station according to the embodiment, the transmission unit includes scheduling information indicating radio resources allocated to the other user terminal to perform the D2D communication in order for the user terminal to measure the reception strength. Send to user terminal.

  In the base station according to the embodiment, the transmission unit transmits decoding information for the user terminal to decode the scheduling information to the user terminal.

  In the base station according to the embodiment, the transmission unit transmits a threshold value used for the user terminal to determine whether or not to transmit the measurement information to the user terminal.

  The user terminal which concerns on embodiment has a user terminal which can establish the connection with the cell which a base station manages, and is a user terminal in the mobile communication system which supports D2D communication which is direct inter-terminal communication. The user terminal, based on the measurement request, a reception unit that receives a measurement request from the base station that requests measurement of reception strength of a signal transmitted from another user terminal that performs the D2D communication A control unit that performs control for measuring the reception intensity of the signal transmitted from the other user terminal, and a transmission unit that transmits measurement information indicating the reception intensity to the base station. The control unit performs control for performing the D2D communication with the other user terminal when the D2D instruction for instructing the user terminal to perform the D2D communication with the other user terminal is received from the base station. .

  In the user terminal according to the embodiment, the transmitting unit transmits the location information of the user terminal to the base station, and the receiving unit receives the measurement request transmitted based on the location information from the base station. To do.

  The user terminal which concerns on embodiment WHEREIN: The said receiving part receives the positional information on the said other user terminal from the said base station, The said control part is based on the said positional information on the said other user terminal, and the said user terminal Is transmitted to the base station indicating that the user terminal exists near the other user terminal, and the receiving unit The measurement request transmitted based on the notification is received from the base station.

  In the user terminal according to the embodiment, the reception unit receives a discovery signal for discovering the partner terminal for D2D communication from the other user terminal, and the transmission unit receives the discovery signal. Discovery information indicating this is transmitted to the base station, and the reception unit receives the measurement request transmitted based on the discovery information from the base station.

  In the user terminal according to the embodiment, the receiving unit receives scheduling information indicating a radio resource allocated to the other user terminal to perform the D2D communication from the base station, and the control unit includes the scheduling Based on the information, control for measuring the reception intensity is performed.

  In the user terminal according to the embodiment, the receiving unit receives decoding information for decoding the scheduling information from the base station, and the control unit decodes the scheduling information using the decoding information.

  In the user terminal according to the embodiment, the control unit performs control to transmit the measurement information to the base station when the reception intensity exceeds a threshold value.

  In an embodiment, the signal is a reference signal used for the D2D communication.

  A processor according to an embodiment includes a user terminal capable of establishing a connection with a cell managed by a base station, and the processor included in the user terminal in a mobile communication system that supports D2D communication that is direct inter-terminal communication It is. The processor executes a process of receiving a measurement request from the base station that requests measurement of reception strength of a signal transmitted from another user terminal that performs the D2D communication, and based on the measurement request , Executing a process of performing control to measure the reception intensity of the signal transmitted from the other user terminal, executing a process of transmitting measurement information indicating the reception intensity to the base station, and the user terminal When a D2D instruction instructing to perform the D2D communication with the other user terminal is received from the base station, a process of performing the D2D communication with the other user terminal is executed.

  Hereinafter, each embodiment in the case of introducing D2D communication into a cellular mobile communication system (hereinafter referred to as “LTE system”) configured in accordance with the 3GPP standard will be described with reference to the drawings.

(LTE system)
FIG. 1 is a configuration diagram of an LTE system according to the present embodiment.

  1, the LTE system includes a plurality of UEs (User Equipment) 100, an E-UTRAN (Evolved Universal Terrestrial Radio Access Network) 10, and an EPC (Evolved Packet Core) 20. The E-UTRAN 10 and the EPC 20 constitute a network.

  The UE 100 is a mobile radio communication device, and performs radio communication with a cell (serving cell) that has established a connection. UE100 is corresponded to a user terminal.

  The E-UTRAN 10 includes a plurality of eNBs 200 (evolved Node-B). The eNB 200 corresponds to a base station. The eNB 200 manages a cell and performs radio communication with the UE 100 that has established a connection with the cell.

  Note that “cell” is used as a term indicating a minimum unit of a radio communication area, and is also used as a term indicating a function of performing radio communication with the UE 100.

  The eNB 200 has, for example, a radio resource management (RRM) function, a user data routing function, and a measurement control function for mobility control and scheduling.

  The EPC 20 includes MME (Mobility Management Entity) / S-GW (Serving-Gateway) 300 and OAM 400 (Operation and Maintenance). The EPC 20 corresponds to a core network.

  The MME is a network node that performs various types of mobility control for the UE 100, and corresponds to a control station. The S-GW is a network node that performs transfer control of user data, and corresponds to an exchange.

  The eNB 200 is connected to each other via the X2 interface. Moreover, eNB200 is connected with MME / S-GW300 via S1 interface.

  The OAM 400 is a server device managed by an operator, and performs maintenance and monitoring of the E-UTRAN 10.

  Next, configurations of the UE 100 and the eNB 200 will be described.

  FIG. 2 is a block diagram of the UE 100. As shown in FIG. 2, the UE 100 includes an antenna 101, a radio transceiver 110, a user interface 120, a GNSS (Global Navigation Satellite System) receiver 130, a battery 140, a memory 150, and a processor 160. Have. The memory 150 and the processor 160 constitute a control unit.

  The UE 100 may not have the GNSS receiver 130. Further, the memory 150 may be integrated with the processor 160, and this set (that is, a chip set) may be used as the processor 160 '.

  The antenna 101 and the wireless transceiver 110 are used for transmitting and receiving wireless signals. The antenna 101 includes a plurality of antenna elements. The radio transceiver 110 converts the baseband signal output from the processor 160 into a radio signal and transmits it from the antenna 101. Further, the radio transceiver 110 converts a radio signal received by the antenna 101 into a baseband signal and outputs the baseband signal to the processor 160.

  The user interface 120 is an interface with a user who owns the UE 100, and includes, for example, a display, a microphone, a speaker, and various buttons. The user interface 120 receives an operation from the user and outputs a signal indicating the content of the operation to the processor 160.

  The GNSS receiver 130 receives a GNSS signal and outputs the received signal to the processor 160 in order to obtain location information indicating the geographical location of the UE 100.

  The battery 140 stores power to be supplied to each block of the UE 100.

  The memory 150 stores a program executed by the processor 160 and information used for processing by the processor 160.

  The processor 160 includes a baseband processor that modulates / demodulates and encodes / decodes a baseband signal, and a CPU (Central Processing Unit) that executes programs stored in the memory 150 and performs various processes. . The processor 160 may further include a codec that performs encoding / decoding of an audio / video signal. The processor 160 executes various processes and various communication protocols described later.

  FIG. 3 is a block diagram of the eNB 200. As illustrated in FIG. 3, the eNB 200 includes an antenna 201, a radio transceiver 210, a network interface 220, a memory 230, and a processor 240. The memory 230 and the processor 240 constitute a control unit. The memory 230 may be integrated with the processor 240, and this set (that is, a chip set) may be used as the processor 240 '.

  The antenna 201 and the wireless transceiver 210 are used for transmitting and receiving wireless signals. The antenna 201 includes a plurality of antenna elements. The wireless transceiver 210 converts the baseband signal output from the processor 240 into a wireless signal and transmits it from the antenna 201. In addition, the radio transceiver 210 converts a radio signal received by the antenna 201 into a baseband signal and outputs the baseband signal to the processor 240.

  The network interface 220 is connected to the neighboring eNB 200 via the X2 interface and is connected to the MME / S-GW 300 via the S1 interface. The network interface 220 is used for communication performed on the X2 interface and communication performed on the S1 interface.

  The memory 230 stores a program executed by the processor 240 and information used for processing by the processor 240.

  The processor 240 includes a baseband processor that performs modulation / demodulation and encoding / decoding of a baseband signal, and a CPU that executes a program stored in the memory 230 and performs various processes. The processor 240 executes various processes and various communication protocols described later.

  FIG. 4 is a protocol stack diagram of a radio interface in the LTE system.

  As shown in FIG. 4, the radio interface protocol is divided into layers 1 to 3 of the OSI reference model, and layer 1 is a physical (PHY) layer. Layer 2 includes a MAC (Media Access Control) layer, an RLC (Radio Link Control) layer, and a PDCP (Packet Data Convergence Protocol) layer. Layer 3 includes an RRC (Radio Resource Control) layer.

  The physical layer performs encoding / decoding, modulation / demodulation, antenna mapping / demapping, and resource mapping / demapping. The physical layer provides a transmission service to an upper layer using a physical channel. Data is transmitted between the physical layer of the UE 100 and the physical layer of the eNB 200 via a physical channel.

  The MAC layer performs data priority control, retransmission processing by hybrid ARQ (HARQ), and the like. Data is transmitted via the transport channel between the MAC layer of the UE 100 and the MAC layer of the eNB 200. The MAC layer of the eNB 200 includes a MAC scheduler that determines an uplink / downlink transport format (transport block size, modulation / coding scheme, and the like) and an allocated resource block.

  The RLC layer transmits data to the RLC layer on the receiving side using functions of the MAC layer and the physical layer. Data is transmitted between the RLC layer of the UE 100 and the RLC layer of the eNB 200 via a logical channel.

  The PDCP layer performs header compression / decompression and encryption / decryption.

  The RRC layer is defined only in the control plane. Control signals (RRC messages) for various settings are transmitted between the RRC layer of the UE 100 and the RRC layer of the eNB 200. The RRC layer controls the logical channel, the transport channel, and the physical channel according to establishment, re-establishment, and release of the radio bearer. If there is an RRC connection between the RRC of the UE 100 and the RRC of the eNB 200, the UE 100 is in a connected state, otherwise, the UE 100 is in an idle state.

  A NAS (Non-Access Stratum) layer located above the RRC layer performs session management, mobility management, and the like.

  FIG. 5 is a configuration diagram of a radio frame used in the LTE system. In the LTE system, OFDMA (Orthogonal Frequency Division Multiplexing Access) is used for the downlink, and SC-FDMA (Single Carrier Frequency Multiple Access) is used for the uplink.

  As shown in FIG. 5, the radio frame is composed of 10 subframes arranged in the time direction, and each subframe is composed of two slots arranged in the time direction. The length of each subframe is 1 ms, and the length of each slot is 0.5 ms. Each subframe includes a plurality of resource blocks (RB) in the frequency direction and includes a plurality of symbols in the time direction. A guard interval called a cyclic prefix (CP) is provided at the head of each symbol. The resource block includes a plurality of subcarriers in the frequency direction. A radio resource unit composed of one subcarrier and one symbol is called a resource element (RE).

  Among radio resources allocated to the UE 100, a frequency resource can be specified by a resource block, and a time resource can be specified by a subframe (or slot).

  In the downlink, the section of the first few symbols of each subframe is a control region mainly used as a physical downlink control channel (PDCCH). The remaining section of each subframe is an area that can be used mainly as a physical downlink shared channel (PDSCH). Further, cell-specific reference signals (CRS) are distributed and arranged in each subframe.

  In the uplink, both ends in the frequency direction in each subframe are control regions mainly used as a physical uplink control channel (PUCCH). Further, the central portion in the frequency direction in each subframe is an area that can be used mainly as a physical uplink shared channel (PUSCH). Further, a demodulation reference signal (DMRS) and a sounding reference signal (SRS) are arranged in each subframe.

(D2D communication)
Next, normal communication (cellular communication) of the LTE system and D2D communication will be compared and described.

  FIG. 6 is a diagram illustrating a data path in cellular communication. Here, the case where cellular communication is performed between UE100-1 which established the connection with eNB200-1 and UE100-2 which established the connection with eNB200-2 is illustrated. A data path means a transfer path of user data (user plane).

  As shown in FIG. 6, the data path of cellular communication goes through the core network. Specifically, a data path that passes through the eNB 200-1, the S-GW 300, and the eNB 200-2 is set.

  FIG. 7 is a diagram illustrating a data path in D2D communication. Here, the case where D2D communication is performed between UE100-1 which established the connection with eNB200-1 and UE100-2 which established the connection with eNB200-2 is illustrated.

  For example, D2D communication is started when one UE 100 of UE 100-1 and UE 100-2 discovers the other UE 100 existing in the vicinity. In order to start D2D communication, the UE 100 has a function of discovering another UE 100 existing in the vicinity of the UE 100 (Discover). Further, the UE 100 has a (Discoverable) function that is discovered from other UEs 100.

  As shown in FIG. 7, the data path of D2D communication does not go through the core network. That is, direct radio communication is performed between UEs. Thus, if UE100-2 exists in the vicinity of UE100-1, by performing D2D communication between UE100-1 and UE100-2, the traffic load of a core network and the battery consumption of UE100 are reduced. Effects such as reduction can be obtained. In the locally routed mode, the data path does not pass through the S-GW 300 but passes through the eNB 200.

(D2D terminal list)
The network manages the UE 100 that performs D2D communication. In this embodiment, eNB200 manages UE100 which has a D2D terminal list and is performing D2D communication using the said D2D terminal list.

  The D2D terminal list is a list of UEs 100 that are performing D2D communication. Specifically, information of the UE 100 that is in the own cell managed by the eNB 200 and performing D2D communication is recorded in the D2D terminal list. Examples of information on the UE 100 include an identifier of the UE 100, location information, an identifier of a communication partner of the UE 100, location information of a communication partner of the UE 100, and an identifier of a cell where the communication partner of the UE 100 is located. In addition, the information of UE100 located in the adjacent cell adjacent to the own cell and performing D2D communication may be recorded.

  In addition, when UE100 exists in the cell, UE100 is the state (connection state) which established the connection with the said cell, or the state (idle state) which was camping on the said cell.

  The eNB 200 records the UE 100 in the D2D terminal list when the UE 100 located in the own cell starts D2D communication or performs D2D communication.

  Moreover, eNB200 deletes UE100 recorded on the D2D terminal list, when UE100 currently recorded on the D2D terminal list complete | finishes D2D communication. In addition, when the UE 100 establishes a connection with a cell managed by the neighboring eNB 200 adjacent to the eNB 200, the eNB 200 may delete the UE 100 recorded in the D2D terminal list. When a connection with another cell is established from the cell, the UE 100 recorded in the D2D terminal list may be deleted.

  The eNB 200 determines whether the UE 100 is performing D2D communication based on the D2D terminal list.

  In addition, eNB200 may acquire D2D terminal list which neighboring eNB200 has from the neighboring eNB200 adjacent to eNB200 via X2 interface regularly or irregularly.

(Schematic operation of the mobile communication system according to the embodiment)
Next, a schematic operation of the mobile communication system according to the embodiment will be described with reference to FIG. FIG. 8 is a sequence diagram illustrating an operation example of the mobile communication system according to the embodiment.

  In this embodiment, UE100-1, UE100-2, and UE100-3 have established the connection with the cell which eNB200 manages. As shown in FIG. 8, in the embodiment, the UE 100-1 performs cellular communication with the UE 100-2 and the UE 100-3 via the eNB 200 and a core network (not shown). Moreover, UE100-2 and UE100-3 are performing D2D communication.

  Note that description will be made assuming that the eNB 200 controls D2D communication between the UE 100-2 and the UE 100-3. Accordingly, the eNB 200 allocates radio resources for the UE 100-2 and the UE 100-3 to perform D2D communication, and transmits scheduling information indicating the allocated radio resources to the UE 100-2 and the UE 100-3.

  In this embodiment, eNB200 performs the process of step S101, when UE100-1 is performing cellular communication with UE100-2 and UE100-3 which are performing D2D communication.

  As illustrated in FIG. 8, in step S101, the eNB 200 determines whether or not the UE 100-1 is present near the UE 100-2 and the UE 100-3 that are counterpart terminals of the cellular communication of the UE 100-1. Specifically, the eNB 200 determines by at least one of the following methods (A) to (D).

(A) Judgment pattern 1
eNB200 judges whether UE100-1 exists near UE100-2 and UE100-3 based on the cell where UE100-1, UE100-2, and UE100-3 exist.

  Specifically, the eNB 200 determines, based on the D2D terminal list, when the cell to which the UE 100-1 is connected is the same as or adjacent to the cell in which at least one of the UE 100-2 and the UE 100-3 is located. Is present near UE 100-2 and UE 100-3. That is, the eNB 200 is configured such that when at least one of the UE 100-2 and the UE 100-3 is located in a cell to which the UE 100-1 is connected or a cell adjacent to the cell, the UE 100-1 is the UE 100-2 or the UE 100-3. Judge that it exists nearby.

  Note that the eNB 200 determines that the UE 100-1 exists near the UE 100-2 and the UE 100-3 when both the UE 100-2 and the UE 100-3 are in the cell to which the UE 100-1 is connected or an adjacent cell. May be.

(B) Judgment pattern 2
eNB200 judges whether UE100-1 exists near UE100-2 and UE100-3 based on each positional information on UE100-1, UE100-2, and UE100-3.

  The eNB 200 is located near the UE 100-2 when the distance between the UE 100-1 and the UE 100-2 is equal to or less than the threshold based on the location information of the UE 100-1 and the location information of the UE 100-2. Judge that. Similarly, the eNB 200 determines whether or not the UE 100-1 exists near the UE 100-3.

  In addition, when the distance between the UE 100-1 and one of the UE 100-2 and the UE 100-3 is equal to or less than the threshold, the eNB 200 causes the distance between the UE 100-1 and the other of the UE 100-2 and the UE 100-3 to be equal to or less than the threshold. You may consider it to be.

  In addition, eNB200 can request | require position information from each of UE100-1, UE100-2, and UE100-3, and can acquire position information from each UE100 (UE100-1, UE100-2, and UE100-3). . Moreover, eNB200 may acquire the positional information on each UE100 from the high-order apparatus of eNB200.

  Also, when the eNB 200 determines that the UE 100-1 does not exist near the UE 100-2 and the UE 100-3, the eNB 200 may request each UE 100 to transmit the location information of each UE 100 regularly or irregularly. The eNB 200 may make a request to periodically transmit the location information to each UE 100. Moreover, eNB200 may request | require each UE100 to transmit the newest position information, when each UE100 leaves | separates more than the predetermined value from the position which the position information transmitted to eNB200 shows.

(C) Judgment pattern 3
The eNB 200 determines whether the UE 100-1 exists near the UE 100-2 and the UE 100-3 based on the proximity notification indicating that the UE 100-1 exists near the UE 100-2 and the UE 100-3. .

  First, eNB200 requests | requires position information from each of UE100-2 and UE100-3, and acquires position information from each of UE100-2 and UE100-3.

  Next, eNB200 transmits each positional information on UE100-2 and UE100-3 to UE100-1. UE100-1 receives each positional information on UE100-2 and UE100-3.

  UE100-1 judges whether UE100-1 exists near UE100-2 and UE100-3 based on each received positional information on UE100-2 and UE100-3. Specifically, when the distance between the UE 100-1 and the UE 100-2 is equal to or less than the threshold based on the current location of the UE 100-1 and the location information of the UE 100-2, the UE 100-1 Is present near the UE 100-2. Similarly, the eNB 200 determines whether or not the UE 100-1 exists near the UE 100-3.

  UE100-1 transmits a proximity | contact notification to eNB200, when it is judged that it exists near UE100-2 and UE100-3.

  When the eNB 200 receives the proximity notification, the eNB 200 determines that the UE 100-1 exists in the vicinity of the UE 100-2 and the UE 100-3.

  In addition, eNB200 may transmit the positional information received from each of UE100-2 and UE100-3 regularly or irregularly to UE100-1.

(D) Judgment pattern 4
Based on discovery information indicating that the eNB 200 has received a discovery signal (hereinafter referred to as a Discovery signal) for discovering a partner terminal for D2D communication, the UE 100-1 is close to the UE 100-2 and the UE 100-3. It is determined whether or not it exists.

  First, the eNB 200 requests the UE 100 at least one of the UE 100-1, the UE 100-2, and the UE 100-3 to transmit a Discovery signal. Here, description will be made assuming that the UE 100-2 and the UE 100-3 have received a Discovery signal transmission request.

  The UE 100-2 and the UE 100-3 transmit a Discovery signal based on the request. UE100-1 transmits the discovery information which shows having received the Discovery signal to eNB200, when the Discovery signal from each of UE100-2 and UE100-3 is received.

  When receiving the discovery information, the eNB 200 determines that the UE 100-1 exists in the vicinity of the UE 100-2 and the UE 100-3.

  When the eNB 200 determines that the UE 100-1 has approached the UE 100-2 and the UE 100-3 according to at least one of the determination patterns (A) to (D) above, the process of step S102 is executed.

  In step S102, the eNB 200 makes a measurement request to the UE 100-1. The UE 100-1 receives the measurement request.

  A measurement request | requirement is the information which requests | requires measuring the receiving strength of the signal transmitted from UE100-2 and UE100-3 which are performing D2D communication.

  Moreover, eNB200 may transmit the scheduling information which shows the radio | wireless resource allocated in order for UE100-2 and UE100-3 to perform D2D communication to UE100-1.

  Moreover, eNB200 may transmit the radio | wireless resource information which shows the radio | wireless resource which transmits scheduling information to UE100-1. UE100-1 can receive scheduling information based on the received radio | wireless resource information.

  Moreover, eNB200 may transmit the decoding information for decoding scheduling information. The UE 100-1 can decode the scheduling information based on the decode information.

  Moreover, eNB200 may transmit the threshold value used in order to judge whether the measurement information mentioned later is transmitted to UE100-1.

  In step S103, UE100-1 measures the signal transmitted from UE100-2 and UE100-3 which are performing D2D communication.

  Since UE100-2 and UE100-3 are performing D2D communication, they are transmitting the D2D signal used for D2D communication. UE100-1 receives the D2D signal transmitted from each of UE100-2 and UE100-3, and measures the received intensity | strength of each received D2D signal.

  The UE 100-1 can estimate the timing at which the UE 100-2 and the UE 100-3 transmit the D2D signal and the frequency band of the D2D signal based on the scheduling information. UE100-1 may measure at the timing which estimated the reception intensity | strength of D2D signal in the estimated frequency band.

  Moreover, UE100-1 may receive the D2D reference signal used for D2D communication transmitted from UE100-2 and UE100-3, and may measure the reception intensity | strength of a D2D reference signal. The D2D reference signal is a signal that the UE 100 performing D2D communication transmits regularly or irregularly with a predetermined radio wave intensity. The D2D reference signal is used, for example, for determining whether or not the UE 100 performing D2D communication can continue the D2D communication. Specifically, the UE 100-2 and the UE 100-3 determine that the D2D communication can be continued by receiving the D2D reference signal with a reception strength equal to or higher than a predetermined value.

  In step S104, UE100-1 transmits the measurement information which shows the received strength of the measured D2D signal to eNB200. The eNB 200 receives the measurement information.

  UE100-1 may transmit measurement information to eNB200 regularly, and UE100-1 may transmit to eNB200, when reception intensity exceeds a predetermined threshold value. The predetermined threshold may be a unique threshold stored in advance in the UE 100-1, or may be a threshold received from the eNB 200 described in step S102.

  In step S105, the eNB 200 determines whether or not the UE 100-1 can perform D2D communication with the UE 100-2 and the UE 100-3. The eNB 200 determines that the UE 100-1 can perform D2D communication with the UE 100-2 and the UE 100-3 when the reception strength of the D2D signal of each of the UE 100-2 and the UE 100-3 is equal to or higher than a predetermined value.

  If the eNB 200 determines that the D2D communication is not possible, the eNB 200 may perform the proximity determination in step S101, or may transmit the measurement request in step S102 regularly or irregularly without performing the proximity determination in step S101. Also good.

  On the other hand, when it is determined that D2D communication is possible, the eNB 200 transmits a D2D instruction instructing to perform D2D communication with the UE 100-2 and the UE 100-3 in Step S106. The UE 100-1 receives the D2D instruction.

  eNB200 may transmit the scheduling information which shows the radio | wireless resource allocated in order for UE100-1, UE100-2, and UE100-3 to perform D2D communication to UE100-1.

  In step S107, UE100-1, UE100-2, and UE100-3 perform D2D setup in order to establish a D2D link. After establishing the D2D link, the UE 100-1, the UE 100-2, and the UE 100-3 perform D2D communication.

  When the D2D link is established, the UE 100-1 may transmit a completion report that reports that the D2D setup is completed to the eNB 200. Or anchor UE100 which communicates with eNB200 on behalf of UE100-1, UE100-2, and UE100-3 may transmit a completion report to eNB200.

  The eNB 200 may update the D2D terminal list based on the completion report, or may update the D2D terminal list when the D2D instruction is transmitted in step S106.

(Summary of the first embodiment)
In this embodiment, eNB200 (radio | wireless transmitter / receiver 210) transmits the measurement request | requirement which requests | requires measuring the reception intensity | strength of D2D signal transmitted from UE100-2 and UE100-3 which are performing D2D communication. UE100-1 (radio | wireless transmitter / receiver 110) receives a measurement request | requirement from eNB200. UE100-1 (a control part and radio | wireless transmitter / receiver 110) measures the reception intensity | strength of the D2D signal transmitted from UE100-2 and UE100-3 based on a measurement request | requirement. UE100-1 (radio | wireless transmitter / receiver 110) transmits the measurement information which shows receiving strength to eNB200. eNB200 (radio | wireless transmitter / receiver 210) receives measurement information from UE100-1. The eNB 200 (control unit) determines whether or not the UE 100-1 is capable of D2D communication based on the measurement information. eNB200 (a control part and the radio | wireless transmitter / receiver 210) transmits D2D instruction | indication which instruct | indicates to perform D2D communication to UE100-1, when UE100-1 judges that D2D communication is possible. UE100-1 (a control part and the radio | wireless transmitter / receiver 110) performs D2D communication with UE100-2 and UE100-3, when receiving D2D instruction | indication which instruct | indicates performing D2D communication from eNB200. Accordingly, the eNB 200 determines whether the UE 100-1 can perform the D2D communication based on the reception strength of the signals from the UE 100-2 and the UE 100-3 performing the D2D communication. It is possible to accurately determine whether communication is possible. Furthermore, since the UE 100-1 performs D2D communication based on the D2D instruction from the eNB 200 when D2D communication is possible, the UE 100-1 can effectively use the D2D communication.

  Moreover, in this embodiment, when UE100-1 is performing cellular communication with UE100-2 and UE100-3, eNB200 (radio | wireless transmitter / receiver 210) transmits a measurement request | requirement, UE100-1 (control part and The radio transceiver 110) measures reception strength when performing cellular communication with the UE 100-2 and the UE 100-3. Thereby, by performing D2D communication instead of cellular communication, while using D2D communication effectively, the load of eNB200 can be reduced.

  Moreover, in this embodiment, eNB200 (control part) is UE100-1 when at least one of UE100-2 and UE100-3 exists in the cell which UE100-1 connects, or the cell adjacent to the said cell. Is determined to exist near the UE 100-2 and the UE 100-3, and the UE 100-1 determines that the D2D communication is possible. Thereby, eNB200 does not need to transmit a useless measurement request, and UE100-1 does not need to measure useless D2D signal.

  Moreover, in this embodiment, UE100-1 (radio | wireless transmitter / receiver 110) transmits the positional information on UE100-1 to eNB200. Based on the location information of the UE 100-1 and the location information of the UE 100-2 and the UE 100-3, the eNB 200 (the control unit and the radio transceiver 210) exists near the UE 100-2 and the UE 100-3. If it is determined to do so, a measurement request is transmitted. UE100-1 (radio | wireless transmitter / receiver 110) receives the measurement request | requirement transmitted based on the positional information from eNB200. Thereby, eNB200 does not need to transmit a useless measurement request, and UE100-1 does not need to measure useless D2D signal.

  Moreover, in this embodiment, UE100-1 (radio | wireless transmitter / receiver 110) receives each positional information on UE100-2 and UE100-3 from eNB200. When the UE 100-1 (the control unit and the radio transceiver 110) determines that the UE 100-2 and the UE 100-3 exist near the UE 100-2 and the UE 100-3 based on the location information of the UE 100-2 and the UE 100-3, Send. The eNB 200 (the control unit and the radio transceiver 210) transmits a measurement request when receiving a proximity notification. UE100-1 (radio | wireless transmitter / receiver 110) receives the measurement request | requirement transmitted based on proximity | contact notification from eNB200. Thereby, eNB200 does not need to transmit a useless measurement request, and UE100-1 does not need to measure useless D2D signal.

  UE100-1 (radio | wireless transmitter / receiver 110) receives a Discovery signal from UE100-2 and UE100-3, and transmits the discovery information which shows having received the Discovery signal to eNB200. eNB200 (a control part and the radio | wireless transmitter / receiver 210) transmits a measurement request | requirement, when discovery information is received from UE100-1. UE100-1 (radio | wireless transmitter / receiver 110) receives the measurement request | requirement transmitted based on discovery information from eNB200. Thereby, eNB200 does not need to transmit a useless measurement request, and UE100-1 does not need to measure useless D2D signal.

  Moreover, in this embodiment, eNB200 (radio | wireless transmitter / receiver 210) transmits the scheduling information which shows the radio | wireless resource allocated in order for UE100-2 and UE100-3 to perform D2D communication to UE100-1. UE100-1 (radio | wireless transmitter / receiver 110) receives scheduling information. UE100-1 (a control part and the radio | wireless transmitter / receiver 110) measures receiving strength based on scheduling information. Thereby, UE100-1 can estimate the timing and frequency band of D2D signal which UE100-2 and UE100-3 transmit D2D signal by scheduling information. The UE 100-1 can efficiently measure the reception intensity by measuring the reception intensity of the D2D signal in the estimated frequency band at the estimated timing.

  Moreover, in this embodiment, eNB200 (radio | wireless transmitter / receiver 210) transmits the decoding information for UE100-1 to decode scheduling information to UE100-1. UE100-1 (radio | wireless transmitter / receiver 110) receives decoding information from eNB200. UE100-1 (control part) decodes scheduling information using decoding information. Thereby, UE100-1 can receive scheduling information and can decode the received scheduling information. The UE 100-1 can efficiently measure the reception strength of the D2D signal based on the decoded scheduling information.

  Moreover, in this embodiment, eNB200 (radio | wireless transmitter / receiver 210) transmits the threshold value used in order to judge whether UE100-1 transmits measurement information to UE100-1. UE100-1 (a control part and the radio | wireless transmitter / receiver 110) transmits measurement information to eNB200, when reception intensity exceeds the said threshold value. Thereby, eNB200 can control transmission of measurement information. For example, the eNB 200 can transmit a threshold value lower than the reference value to the UE 100-1 when permitting D2D communication with transmission power equal to or higher than a predetermined value. On the other hand, the eNB 200 can transmit a threshold value higher than the reference value to the UE 100-1 when permitting D2D communication only with transmission power less than a predetermined value.

  In the present embodiment, the D2D signal may be a D2D reference signal used for D2D communication. Since the D2D reference signal can be used to determine whether or not the D2D communication can be continued, by measuring the reception intensity of the D2D reference signal, it is possible to guarantee the stable D2D communication, and then the UE 100-1 Can start D2D communication.

[Other embodiments]
As mentioned above, although this invention was described by embodiment, it should not be understood that the description and drawing which form a part of this indication limit this invention. From this disclosure, various alternative embodiments, examples and operational techniques will be apparent to those skilled in the art.

  For example, in the above-described embodiment, the UE 100-1 performs cellular communication with the UE 100-2 and the UE 100-3, but is not limited thereto. Even if UE100-1 performs cellular communication only with UE100-2 and is not communicating with UE100-3, eNB200 may transmit a measurement request | requirement. That is, the eNB 200 performs cellular communication with at least one UE 100 among the plurality of UEs 100 performing D2D communication, and transmits a measurement request to the UE 100 that does not perform D2D communication with the plurality of UEs 100. Good.

  Moreover, in embodiment mentioned above, when eNB200 is performing cellular communication with UE100-2 and UE100-3, although the measurement request | requirement was transmitted to UE100-1, it is not restricted to this. When UE 100-1 requests cellular communication or D2D communication with UE 100 performing D2D communication as a communication partner, the measurement request may be transmitted.

  In the above-described embodiment, the eNB 200 transmits the measurement request when the UE 100-1 exists in the vicinity of the UE 100-2 and the UE 100-3, but is not limited thereto. The eNB 200 may transmit a measurement request without making a proximity determination.

  Moreover, in embodiment mentioned above, although UE100-1 measured the reception intensity | strength of each D2D signal of UE100-2 and UE100-3, it is not restricted to this. For example, when the UE 100-1 is performing cellular communication with the UE 100-2, the UE 100-1 may measure the reception strength of the D2D signal of the UE 100-1, and may not measure the reception strength of the UE 100-3. Therefore, UE100-1 may transmit the measurement information which shows the receiving strength of the signal only of UE100-2 to eNB200. In addition, when there is an anchor UE 100 that performs communication with the eNB 200 for D2D communication, the UE 100-1 measures the reception strength of the D2D signal of the anchor UE 100 and measures the reception strength of the other UE 100. It does not have to be. In this case, the eNB 200 transmits the identifier of the anchor UE 100 to the UE 100, and the UE 100-1 measures the reception strength of the D2D signal of the anchor UE 100 based on the identifier.

  Moreover, although eNB200 transmitted D2D instruction | indication to UE100-1 in embodiment mentioned above, it is not restricted to this. The eNB 200 may transmit a D2D instruction not only to the UE 100-1, but also to the UE 100-2 and the UE 100-3. Further, when the anchor UE 100 exists, the anchor UE 100 may be instructed to perform D2D communication.

  Moreover, although eNB200 transmitted scheduling information to UE100-1 in embodiment mentioned above, it is not restricted to this. UE100-1 may receive based on the radio | wireless resource information which shows the radio | wireless resource which transmits the scheduling information addressed to UE100-2 and UE100-3 instead of addressing to UE100-1. Furthermore, the UE 100-1 can decode the scheduling information based on the received scheduling information based on the decoding information.

  In the above-described embodiment, the eNB 200 determines whether or not the UE 100-1 can perform D2D communication with the UE 100-2 and the UE 100-3, but is not limited thereto. For example, a host device (e.g., MME) of the eNB 200 may manage the UE 100 performing D2D communication using the D2D terminal list. That is, the host device of the eNB 200 may determine whether or not the UE 100-1 can perform D2D communication with the UE 100-2 and the UE 100-3. Further, the host device of the eNB 200 may determine whether or not the UE 100-1 exists near the UE 100-2 and the UE 100-3.

  DESCRIPTION OF SYMBOLS 10 ... E-UTRAN, 20 ... EPC, 100, 100-1, 100-2, 100-3 ... UE (user terminal), 101 ... Antenna, 110 ... Radio transceiver, 120 ... User interface, 130 ... GNSS receiver 140 ... battery 150 ... memory 160,160 '... processor 200,200-1,200-2,200-3 ... eNB (radio base station) 201 ... antenna 210 ... radio transceiver 220 ... network Interface 230 ... Memory 240, 240 '... Processor 300 ... MME / S-GW 400 ... OAM

Claims (4)

The base station in a mobile communication system having a user terminal capable of establishing a connection with a cell managed by the base station and supporting direct inter-terminal communication,
A threshold used for determining whether or not to transmit measurement information related to the reception intensity of the D2D reference signal transmitted from another user terminal that performs direct inter-terminal communication, and radio used for direct inter-terminal communication A transmission unit for transmitting information indicating a resource to the user terminal;
A receiving unit that receives the measurement information from the user terminal when the measurement information about the radio resource exceeds the threshold;
And a control unit capable of performing control for direct inter-terminal communication based on the measurement information. A user terminal capable of establishing a connection with a cell managed by a base station, the user terminal in a mobile communication system supporting direct inter-terminal communication,
A threshold used for determining whether or not to transmit measurement information related to the reception intensity of the D2D reference signal transmitted from another user terminal that performs direct inter-terminal communication, and radio used for direct inter-terminal communication A receiver that receives information indicating a resource from the base station;
A control unit that measures the reception strength of the D2D reference signal transmitted from the other user terminal in the radio resource and generates the measurement information;
A transmitter that transmits the measurement information to the base station when the measurement information about the radio resource exceeds the threshold; and
The user terminal, wherein the measurement information can be used for control for direct inter-terminal communication by the base station. A processor for a user terminal in a mobile communication system having a user terminal capable of establishing a connection with a cell managed by a base station and supporting direct inter-terminal communication,
A threshold used for determining whether or not to transmit measurement information related to the reception intensity of the D2D reference signal transmitted from another user terminal that performs direct inter-terminal communication, and radio used for direct inter-terminal communication A process of receiving information indicating a resource from the base station;
Measuring the reception strength of the D2D reference signal transmitted from the other user terminal in the radio resource and generating the measurement information;
When the measurement information on the radio resource exceeds the threshold, a process of transmitting the measurement information to the base station is executed.
The processor, wherein the measurement information can be used for control for direct terminal-to-terminal communication by the base station. A method in a mobile communication system that supports direct terminal-to-terminal communication,
Measurement information regarding the reception strength of the D2D reference signal transmitted from another user terminal that performs direct inter-terminal communication to a user terminal that can establish a connection with a cell managed by the base station. Transmitting a threshold used to determine whether to transmit and information indicating radio resources used for direct inter-terminal communication ;
The user terminal receiving the threshold and information indicating the radio resource from the base station;
The user terminal performing a process of generating the measurement information by measuring the reception strength of the D2D reference signal transmitted from the other user terminal in the radio resource ;
The user terminal, when the measurement information on the radio resource exceeds the threshold, transmitting the measurement information to the base station;
The base station receiving the measurement information from the user terminal whose measurement information exceeds the threshold; and
The measurement information can be used by the base station for control for direct terminal-to-terminal communication.

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